Gale Warning 475, NWS Anchorage, AK

525 
FZAK62 PAFC 122336
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
336 PM AKDT Thu Oct 12 2017

Offshore Waters Forecast for the Bering Sea

Wind forecasts reflect the predominant speed and direction
expected. Sea forecasts represent an average of the highest
one-third of the combined wind wave and swell height.

PKZ499-131345-
336 PM AKDT Thu Oct 12 2017
.SYNOPSIS FOR CENTRAL BERING SEA...

A 963 mb low at 62N 179E moves to 66N 176E at 977 mb Fri afternoon
and then remains nearly stationary and weakens through Sat. A 998
mb low at 51N 176W Fri morning moves to 56N 153W at 990 mb Sat 
afternoon.

$$

PKZ411-131345-
Bering Sea Offshore West of 180 and East of the International
Dateline-
336 PM AKDT Thu Oct 12 2017

...GALE WARNING TONIGHT...

.TONIGHT...SW wind 25 to 40 kt. Seas 15 to 26 ft.
.FRI...W wind 20 to 30 kt. Seas 12 to 18 ft.
.FRI NIGHT...W wind 20 to 30 kt. Seas 12 ft.
.SAT...W wind 20 to 30 kt. Seas 11 ft.
.SAT NIGHT...W wind 25 kt. Seas 10 ft.
.SUN THROUGH TUE...NW wind 10 to 25 kt. Seas 7 to 12 ft.

$$

PKZ412-131345-
Bering Sea Offshore 171W to 180 and North of 56N-
336 PM AKDT Thu Oct 12 2017

...GALE WARNING TONIGHT...

.TONIGHT...SW wind 40 kt. Seas 21 to 30 ft.
.FRI...SW wind 15 to 30 kt. Seas 14 to 21 ft.
.FRI NIGHT...SW wind 10 to 25 kt. Seas 13 ft.
.SAT...W wind 15 to 25 kt. Seas 11 ft.
.SAT NIGHT...W wind 15 to 25 kt. Seas 10 ft.
.SUN...W wind 25 kt. Seas 10 ft.
.MON...W wind up to 20 kt. Seas 4 to 9 ft.
.TUE...NW wind 15 kt. Seas 7 to 12 ft.

$$

PKZ413-131345-
Bering Sea Offshore 171W to 180 and South of 56N-
336 PM AKDT Thu Oct 12 2017

...GALE WARNING TONIGHT...

.TONIGHT...SW wind 35 kt. Seas 18 to 27 ft.
.FRI...SW wind 10 to 25 kt. Seas 12 to 19 ft.
.FRI NIGHT...W wind 15 to 30 kt. Seas 13 ft.
.SAT...W wind 25 kt. Seas 12 ft.
.SAT NIGHT...W wind 15 to 25 kt. Seas 9 to 12 ft.
.SUN...W wind 25 kt. Seas 10 ft.
.MON...SW wind up to 15 kt. Seas 5 to 9 ft.
.TUE...NW wind up to 20 kt. Seas 10 to 18 ft.

$$

PKZ414-131345-
Bering Sea Offshore East of 171W-
336 PM AKDT Thu Oct 12 2017

...GALE WARNING TONIGHT...

.TONIGHT...SW wind 35 kt. Seas 16 to 24 ft.
.FRI...S wind 25 kt. Seas 13 to 19 ft.
.FRI NIGHT...SE wind 15 to 30 kt becoming NW after midnight. Seas
10 to 15 ft.
.SAT...W wind 10 to 25 kt. Seas 10 ft.
.SAT NIGHT...W wind 15 to 25 kt. Seas 7 to 11 ft.
.SUN THROUGH MON...SW wind 10 to 25 kt. Seas 5 to 10 ft.
.TUE...NW wind up to 20 kt. Seas 7 to 12 ft.

$$

573 
FZAK62 PAFC 131151
OFFALU

Offshore Waters Forecast
National Weather Service Anchorage AK
351 AM AKDT Fri Oct 13 2017

Offshore Waters Forecast for the Bering Sea

Wind forecasts reflect the predominant speed and direction
expected. Sea forecasts represent an average of the highest
one-third of the combined wind wave and swell height.

PKZ499-140115-
351 AM AKDT Fri Oct 13 2017
.SYNOPSIS FOR CENTRAL BERING SEA...
A 1007 mb low at 48N 179E deepens to 995 mb near 55N 161W Sat 
morning before continuing to 56N 142W at 997 mb by Sun morning. The 
associated front extends across the Gulf of Alaska and south of the 
Aleutians through Sun morning. Several troughs move over the Bering 
through Sun morning.

$$

PKZ411-140115-
Bering Sea Offshore West of 180 and East of the International
Dateline-
351 AM AKDT Fri Oct 13 2017

.TODAY...SW wind 20 to 30 kt. Seas 11 to 18 ft.
.TONIGHT...W wind 15 to 30 kt. Seas 11 ft.
.SAT...W wind 20 to 30 kt. Seas 11 ft.
.SAT NIGHT...W wind 25 kt. Seas 10 ft.
.SUN...SW wind 10 to 25 kt. Seas 7 to 10 ft.
.MON...NE wind 10 to 25 kt. Seas 5 to 10 ft.
.TUE...NW wind 10 to 20 kt. Seas 6 to 9 ft.

$$

PKZ412-140115-
Bering Sea Offshore 171W to 180 and North of 56N-
351 AM AKDT Fri Oct 13 2017

.TODAY...SW wind 20 to 30 kt. Seas 14 to 21 ft.
.TONIGHT...SW wind 15 to 25 kt. Seas 12 ft.
.SAT...SW wind 10 to 25 kt. Seas 10 ft.
.SAT NIGHT...W wind 15 to 25 kt. Seas 10 ft.
.SUN...W wind 10 to 25 kt. Seas 9 ft.
.MON...SE wind up to 15 kt. Seas 5 to 8 ft.
.TUE...NW wind 15 kt. Seas 5 to 8 ft.

$$

PKZ413-140115-
Bering Sea Offshore 171W to 180 and South of 56N-
351 AM AKDT Fri Oct 13 2017

.TODAY...SW wind 15 to 25 kt. Seas 12 to 19 ft.
.TONIGHT...W wind 15 to 25 kt. Seas 12 ft.
.SAT...W wind 15 to 25 kt. Seas 11 ft.
.SAT NIGHT...W wind 15 to 25 kt. Seas 10 ft.
.SUN...W wind 10 to 25 kt. Seas 7 to 11 ft.
.MON...S wind up to 20 kt. Seas 4 to 9 ft.
.TUE...NW wind 10 to 20 kt. Seas 7 to 11 ft.

$$

PKZ414-140115-
Bering Sea Offshore East of 171W-
351 AM AKDT Fri Oct 13 2017

.TODAY...SW wind 15 to 25 kt. Seas 12 to 19 ft.
.TONIGHT...SW wind 10 to 20 kt. Seas 10 to 13 ft.
.SAT...W wind 10 to 20 kt. Seas 9 ft.
.SAT NIGHT...W wind 20 kt. Seas 6 to 9 ft.
.SUN...W wind 20 kt. Seas 6 to 10 ft.
.MON...S wind 15 kt. Seas 4 to 8 ft.
.TUE...NW wind 10 to 20 kt. Seas 4 to 8 ft.

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
420 PM AKDT Wed Oct 11 2017

.ANALYSIS AND UPPER LEVELS...
An amplifying upper level ridge is tracking across the mainland
part of the state today as it is being pushed eastward by a strong
upper level low in the northwest Bering Sea. The jet stream is
wrapping around the low to the south and then moves over the north
side of the ridge. This is bringing strong southerly flow over the
central Bering Sea.
At the surface the low is in the northwest Bering Sea and around
958 mb this afternoon. This large low encompasses the entire
Bering Sea and into Southwest Alaska.

&&

.MODEL DISCUSSION...
Models are in good agreement with the significant exception of a
low tracking rapidly near the Aleutians and into Bristol Bay or
the AK Peninsula Friday into Saturday. This is a pattern where
models typically struggle. The GFS is by far the most northerly
brining it onshore near Dillingham. The ECMWF is holding firm
with a solution taking it south of the Alaska Peninsula. The
Canadian and NAM are in between but differ in speed. All solutions
are significantly farther south than yesterday. Afternoon
forecasts reflect a track through the center of Bristol Bay,
which looks likely at this point. This track will minimize the
chance of any coastal flooding with the weekend low.

&&

.AVIATION...
PANC...VFR conditions and light winds will remain for the rest of
the night. Rain should move into the area tomorrow but conditions
will likely remain mostly VFR as southeasterly flow helps keep
ceilings in the 3500 to 5000 ft range.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...
An amplifying ridge building in over the Mainland this evening
will maintain westerly flow across the Gulf, along with some weak
gap winds along the north Gulf coast. Mostly drier and cloudy
conditions are expected through Thursday morning, with a few
lingering showers over the Susitna Valley and Copper River Basin.
The focus will then shift to a large storm system tracking over
the far western Bering Sea, and the associated front marching
eastward into the western Gulf by Thursday morning. As is so often
the case, expect development of a triple point low over the far
western Gulf as the frontal system makes its way through the
western Gulf. This will lead to strengthening low level
southeasterly winds ahead of the low on Thursday, from the
northern Gulf across Prince William Sound to the Kenai Peninsula,
Turnagain Arm and Anchorage. However, instead of downslope drying,
deep and moist southwest flow aloft combined with a series of
sharp upper level short-waves will lead to steady rainfall for the
population centers Thursday through Friday morning. Strong gusty
gap winds are also expected to develop along Turnagain arm
Thursday, and diminish Friday morning.

Marginally colder air will filter into Southcentral overnight
Thursday into Friday, leading to falling snow levels area-wide.
Upslope flow along the west side of the Chugach and Talkeetna
Mountains combined with potential for locally heavy precipitation
as a short-wave moves through the region could lower snow levels
even more. For now, we have kept the potential for snowfall over
the Copper River Basin, and along the higher elevations of the
Chugach and Talkeetna mountains.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...

The southwest coast of Alaska is experiencing gusty south to
southeasterly winds this afternoon as a front approaches the
shore. Expect winds to taper off overnight as the front moves
onshore and weakens. Rain associated with the front has already
reached the lower Kuskokwim Delta and Bristol Bay area. As the
front pushes east tonight, expect rain to continue through
Thursday, tapering off from west to east Thursday afternoon.
Behind the front, continued strong southwesterly flow over the
Bering Sea will raise water levels along coastal areas of the
Kuskokwim Delta Thursday. Minor flooding of coastal low lying
areas is possible during high tide Thursday afternoon. Once the
front has pushed through the area, temperatures will cool
throughout the day Thursday. Friday will be cooler and showery
with temperatures returning to near normal for this time of year
after a few relatively warm (albeit wet) days.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...

The low pressure system over the western Bering Sea will reach
peak intensity overnight before beginning to gradually weaken
Thursday morning. A swath of storm force winds over the western
Aleutians and western Bering will weaken to gale force as the
system moves north Thursday afternoon. By late Thursday night,
this low will move into eastern Siberia, leaving much of the
Bering Sea in a broad cyclonic, showery pattern overnight.
The next system to impact the area will approach the western and
central Aleutians from the southwest Friday morning. A strong
zonal jet to the south of the western Aleutians will move the
feature quickly east, however models are struggling with the exact
track and intensity of the low. Current thinking is that the low
will move along the base of the longwave trough, tracking eastward
just to the north of the Alaska Peninsula Friday through Friday
evening, then crossing into the western Gulf by Saturday morning.
The main impacts of this low will be felt along the Aleutians,
with a small swath of storm force winds possible around the
central and eastern Aleutians Friday night. With the difficulties
in the handling of this system, forecast confidence in the exact
placement of the strongest core of winds is fairly low.

&&

.LONG TERM FORECAST (Days 3 through 7)...

Saturday, the models have a low near the AKPEN. There have been
some major model discrepancies with the track of the low. The
ECMWF has brought the surface low south of the AKPEN while the GFS
has kept it well north of the AKPEN. The NAM is trending slightly
more to the south. There is still a lot of uncertainty with this
storm and it will impact everything from potential storm surge
issues to rainfall amounts. Given the vagaries of the models,
expect more updates associated with this system. Next week, the
pattern stays very active across the Bering Sea. As the zonal jet
continues, expect new systems to be steered across the AKPEN and
into the Gulf. This would result in calmer and clearer weather
across the mainland. The models are picking up on colder air
pooling up over the interior and spilling over the Alaska Range.
Increasing confidence that there will be a cold air outbreak by
the middle of next week.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...High Wind Warning 191
MARINE...None.

&&

SYNOPSIS AND MODEL DISCUSSION...EZ
SOUTHCENTRAL ALASKA...TP
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...RD
LONG TERM...PS